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Understanding the Urine Albumin-to-Creatinine Ratio (ACR) Test

One of the basic kidney function tests that your health care provider will likely order is a simple urine test. If you’ve had a standard physical exam at some point, you’ve probably given a urine sample as part of the exam’s lab work. One of the tests that can be done on a urine sample is a check for a specific protein called albumin.

Albumin and the Kidneys

  • Albumin is a healthy protein that travels through your bloodstream. When the kidneys filter your blood, they separate waste products from healthy substances in the blood including albumin. If your kidneys are impaired, however, they may filter some albumin out with the waste products, which means some albumin will wind up in your urine.

  • Creatinine is a waste product created by the normal breakdown of muscle cells in your body. It is one of the substances that healthy kidneys filter out of the bloodstream, so it should be present in your urine. When kidneys are not functioning properly, however, some creatinine is not filtered, typically leading to a buildup of creatinine in the bloodstream and less creatinine in the urine.

  • Your health care provider can determine whether or not albumin is in your urine by inserting a treated dipstick into the sample. The dipstick changes colors to show how much albumin is present. This is sometimes called a microalbumin test because it’s a good way to measure small amounts of albumin in the urine.

What does the Albumin-to-Creatinine Ratio (ACR) Mean?

The ratio of albumin to creatinine in your urine gives a good indication of how well your kidneys are functioning, especially if you have diabetes. Along with the glomerular filtration ratio (GFR) test, ACR is one of the standard tests your health care provider uses.

ACR result
What the number means

less than 30 mg/g

Your kidneys are filtering properly.

more than 30 mg/g but less than 300 mg/g

Your kidneys are leaking albumin and failing to filter out creatinine. You will probably be tested again in 1 or 2 weeks to confirm this result. This condition is called microalbuminuria.

more than 300 mg/g

Your kidneys are not filtering properly. The condition is called macroalbuminuria.

Your health care provider will consider your ACR along with the results of other tests in making a diagnosis and creating a treatment plan. It is very important that you follow the directions that your health care provider gives you.

This program is supported by

Boehringer Ingelheim Pharmaceuticals, Inc.





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